The present invention relates to an apparatus and a method for decontamination of objects, in particular for detoxification or disinfection of small, temperature-sensitive military devices.
In terms of the present invention, decontamination means specific eradication/removal of radioactive substances and/or specifically rendering safe or removing biological or chemical substances which, without such measures, would represent a hazard to the health or even to the life of personnel. Such substances may be the result of the use of NBC agents for military or terrorist purposes. Furthermore, the substances may also lead to contamination of personnel or object as a result of accidents. Decontamination measures include nuclear radiation eradication (N decontamination), disinfection (B decontamination) and detoxification (C decontamination), with different decontamination agents and procedures being used depending on the nature of the decontamination. The present invention relates in particular to the detoxification and disinfection of small temperature-sensitive appliances, for example of telescopic sights or other optical or electronic components.
German patent application DE 34 29 346 A1 discloses a decontamination method in which a mixture of hot air and steam is used as decontamination agent. Any other heated gas instead of hot air may allegedly be used. In particular, the use of exhaust gases from combustion processes is proposed. An important factor for the success of this known method is the high temperatures of, for example, 170° C. This known method is therefore not suitable for decontamination of temperature-sensitive objects. Furthermore, the known method does not ensure reliable disinfection in the case of critical biological agents, such as mycotoxins or anthrax spores.
The method known from DE 34 29 346 A1 differs from another known method, which is mentioned in the introductory portion of the specification in DE 34 29 346 A1, by the use of a hot-air/hot-gas-vapor mixture at ambient pressure. In the case of the latter, the decontamination is carried out solely by means of hot vapor at a maximum pressure of 4 bar. The decontaminated objects are dried with hot air in a phase that follows. However, this known method also does not ensure adequate disinfection of critical biological agents, and, furthermore, it is not suitable for detoxification of temperature-sensitive objects.
DE 36 25 847 A1 discloses a decontamination chamber which is intended in particular for decontamination of items of clothing. In this case as well, a hot-gas/vapor mixture is used as the decontamination agent, using flue gases or exhaust gases from combustion processes. In the case of this known decontamination chamber, the decontamination process is once again carried out at high temperatures and at ambient pressure.
DE 34 13 743 A1 and DE 38 35 857 A1 both disclose apparatuses for the production of hot vapor for decontamination of items of clothing and equipment. The use of hot vapor and, in addition to this, the use of combustion exhaust gases as a decontamination agent also makes these known apparatuses unsuitable for the decontamination of temperature-sensitive items of equipment, however. Furthermore, these known methods also do not ensure adequate decontamination of critical biological agents.
Various methods for disinfection of objects are known from the so-called RKI list, which is issued by the Robert-Koch Institute in Germany and is published in the Federal Health Gazette (“Bundesgesundheitsblatt”) of the Federal Republic of Germany No. 1-2003. A distinction is made between thermal methods and chemical methods. The former generally make use of hot vapor for disinfection, with the objects to be disinfected being accommodated in a chamber which is repeatedly evacuated and into which vapor pulses are then introduced. Methods are mentioned which operate with a vapor temperature of 75° C., which is a relatively low temperature in comparison to the decontamination methods described above. The chemical disinfection methods are based primarily on the use of chemical disinfection agents, such as formaldehyde, peracetic acid or chlorine. The RKI list also mentions chemo-thermal disinfection washing methods in which washing is carried out using chemical disinfection and cleaning agents at temperatures from 60° C. to 70° C.
DE 29 21 915 A1 describes an apparatus and a method for sterilization of thermally unstable materials in the medical field. The goal is to satisfactorily sterilize objects with narrow tubes or flexible tubes, such as endoscopes or catheters. Since small condensation droplets can block the pores and capillaries of such objects and can then absorb a disinfection agent in the form of vapor, the sterilization chamber is first of all repeatedly and alternately purged with an agent gas, and is ventilated again. By way of example, the sterilization chamber is first filled with water-aldehyde vapor at a reduced pressure of, for example 6 kPa. The chamber is filled to a pressure which is below the saturation pressure, for example to 16 kPa. The air-aldehyde-vapor mixture is then sucked off again down to a value of, for example 6 kPa. This process is repeated several times until it can be assumed that even very small cavities in the object to be sterilized have been filled with the agent gas. The operating pressure in the sterilization chamber is then raised above the saturation value of the agent, and is kept constant throughout a time during which it acts. The actual sterilization process is therefore carried out at a pressure which is above the saturation pressure, so that the agent is partially in condensed form.